Abstract
Despite its similarities in bulk properties to Earth, Venus portrays a fundamentally different mode of surface tectonics. Venus is currently known to be operating in stagnant lid mode of mantle convection. However, it is debated to have an episodic lid regime with long quiescent periods, broken by rapid subduction-driven plate recycling, that recycles the crust globally over geologically short periods of time. However, the tesserae regions, that cover approximately 10 \% of the surface of the planet may be older than the remaining surface. The composition and age of the tesserae are still unknown, but they are observed to be strongly deformed and might therefore have survived the global recycling events. It has therefore been suggested that these tesserae may in some ways be comparable to continents on Earth, since these are areas that do not participate in subduction. Based on previous work on mantle convection modelling on Venus with and without cratons, this project aims to further the knowledge of possible cratons on Venus and their impact on the mantle dynamics and proposed overturn events. By thermochemical modelling carried out with the StagYY code, models with a varying number of cratons and varying yield stress are produced in 2D and 3D. The cratons' impact on the mantle is investigated by examining the number of mantle plumes, the thermal evolution, the crustal thickness and the surface age. The findings show that the number, timing and mode of overturns are highly dependent on yield stress and in some degree dependent on pre-imposed cratons. The cratons have a significant effect on the wavelength of convection in the mantle, which may lead to changes in plume patterns and overturn initiation.